Gordon



March 3, 1964 J. GORDON- 3,123,731

HYDRAULIC ACTUATED BRUSH AND HOLDER Filed April 20, 1961 2 Sheets-Sheet 1 ill WWW

u M M I INVENTO 9. JAMES Gannon March 3, 1964 J. GORDON 3,123,731

HYDRAULIC ACTUATED BRUSH AND HOLDER Filed April 20. 1961 2 Sheets-Sheet 2 INVENTOR JAMES Gonoeu 3,123,731 HYDRAULHQ ACTUA'I'ED BRUSH AND HGLDER James Gordon, 3625 N. Halstctl St, Chicago, Ill. Filed Apr. 29, 1961, Ser. No. 1il4,347 4 Claims. (Cl. 310-443) This invention relates to the transmission of electrical energy to and from the commutator of a dynamo electric machine, more particularly it relates. to a new and improved system for maintaining and urging the brushes of said machine in contact with said commutator.

The brushes in a dynamo electric machine form a conduit for electrical energy being transmitted to or from the commutator. It is well known that the most desirable connection between a brush and a rotating commutator is attained when there is a constant force urging the brush against the commutator. When a constant force is not applied, this results in either unnecessary wear on the brush when too much force is applied or the loss of electrical energy through electrical arcing when too little force is applied.

In the prior art, the application of urging force on the brushes is accomplished through mechanical means such, for example, as spring biasing means. Springs used in this manner have many drawbacks. A primary drawback is evident when the brushes are worn down. The springs must fully elongate themselves to urge and maintain the brushes against the commutator thereby losing their capabiiity to exert their initial force on the brushes. When the springs cannot exert a suitable force on their brushes, they must be replacedv This, of course, means that manpower must be used and down time on the machine is increased because they must be stopped to enable replacement of the brushes. Also there is minute bouncing when siring pressure is used. The minute bouncing" not only results in wear on the brush but also the heat generated from the bouncing causes wear and distortion on the brush holder, thereby limiting the life of both the brush holder and the brush.

To obviate these disadvantages, the prior art teaches structures where the springs can be adjusted so that they maintain their initial biasing force regardless of the position of the brushes. The disadvantage of having this type of structure is that it is not self adjusting and therefore requires attention from someone. Furthermore, because the spring must be adjusted in steps, it is very ditfic-ult to keep the spring exerting aconstant pressure. Also, since this adjustable structure does not truly exert a constant and equal force, it has minute bouncing and all the disadvantages which are present therewith.

My invention obviates the difficulties involved with prior art systems for holding the brushes by providing fluid means such as a hydraulic system that maintains a constant and equal pressure on the brushes and advances the brushes automatically toward the commutator as the brushes are worn down.

it is therefore an object of this invention to provide a new and improved brush holder for a dynamoelectric machine which has a commutator and brush combination.

It is also an object of this invention to provide a fluid means for maintaining and urging the brushes of a dynamoelectric machine against their commutator with a constant and equal force.

Still further, it is an object of my invention to provide a hydraulic system for maintaining and urging the brushes of a dynamoelectric machine against their commutator with a constant and equal force.

ven still further, it is an object of this invention to provide automatic means for maintaining and urging the brushes of a dynainoelectric machine into contact with their commutator.

nitcd rates Patent 3,123,731 Patented Mar. 3, 1964 Other objects and advantages which are intended to be within the scope of this invention will be readily apparent to one ski-lied in the art upon reading the following specification and its appended claims wherein:

FIG. 1 is an elevational view showing the relationship of my new and improved brush holders and hydraulic system with the commutator of a dynamoelectric machine (not shown).

FIG. 2. is an enlarged halsfisectional view taken on a plane through the line 22. and looking in the direction of the arrows in H6. 1.

FIG. 3 is a rear view of the master cylinder illustrated in FIGS. 1 and 2.

PEG. 4 is an enlarged half-sectional view of one of my brush holders taken on a plane through line 4-4 looking in the direction of the arrows.

FIG. 5 is a side view of FIG. 4 taken on a plane through the line 5-5 looking in the direction of the arrows.

FIG. 6 is a sectional view taken on a plane through the line o-6 looking in the direction of the arrows.

PIG. 7 is a sectional view taken on a plane through the line 77 looking in the direction of the arrows.

FIG. 8 is a partial portion of the sectional view illustrated in FlG. 2, said view illustrating my master cylinders spring in its locked position.

H6. 9 is a partial sectional view taken along the line 99 in FIG. 2 looking in the direction of the arrows.

Referring generally to the drawing, a plurality of brush holders are illustrated with the commutator of a dynainoelectric machine (not shown). The brush holders each have a brush therein which is urged in contact with the commutator by a diaphragm disposed in each brush holder. Each brush holder is hydraulically connected to a master cylinder to form a constant volume system whereby a constant force is exerted on each diaphragm regardless of the position of its corresponding brush. Therefore when the brushes are Worn down, they are advanced toward the commutator and held in contact therewith by a constant force. As the brushes are advanced, the volume of the hydraulic system remains constant because the master cylinder readjusts the volume or" the system through the use of adiaphragm.

Although my invention employs diaphragrns and a particular hydraulic system to actuate the brushes, I intend that its scope shall include any brush holders having a hydraulic system that keeps the brushes in contact with the commutator. Also this invention should not only be limited to a hydraulic system but rather it is intended that its scope should include any type of fluid system, such as a gas system for example.

Referring more specifically to the drawing, four brush holders ltl are illustrated in combination with a rotating commutator =12, which is electrically connected to a dynainoelectric machine (not shown). Fron FIG. 1, it is seen that these bnush holders it] are hydraulically connected to a master cylinder 34 through conduits 19.

rush H olders As clearly illustrated in FlG. 4-, each brush holder Ill has a brush l4 disposed therein and urged in contact with the commutator 12 by a hydraulic reservoir 16. Diaphragms 18 are interposed between the hydraulic reservoirs l6 and the brushes 14 whereby the hydraulic reservoirs l6 exert force on the brushes 14 by pressing the diaphragms 13 against the brushes. The diaphragm may be composed of any type of material that has such characteristics of, among others, flexibility, resistance to acids or alkalis, imperviousness to the fiow of fluids and elasticity. For example, such well xnown materials as synthetic rubber, plastic, or impregnated cloth could be used.

The brush holders it of my invention basically comprise a brush positioner 2i and a brush cylinder 21. Each of the brush positioners 20 has a rectangular bore 22 therein which has the head 14a of its corresponding brush 14 protruding therethrough to contact the commutator 12. FIG. 4 illustrates a cross section of the brush cylinder 21 and the brush positioner 2h. The brush heads 14a of the brush 14 are in contact with the walls of the rectangular bores 22 and have a sliding relationship therewith. Also, as can be seen from the drawing, there is a slot 29 in each brush positioner 24 The slot 2? serves the purpose of enabling a lead 23, which is attached to the brush head 14a, to be connected to an outside electrical source. The slot 29 also enables the brush 14 to be actuated toward the commutator 12 without losing its connection when the brush head 14a is worn down. The lead 23 can move along the slot 29 as the brush 14 is actuated toward the commutator 12.

The brush positioner 2% is assembled with the brush cylinder 21 in a male and female relationship. The brush positioner 2 3 has an outer rear cylindrical portion 26 which plugs snugly inside a cylindrical shoulder portion 28 of the brush cylinder 21. The brush cylinder 21 has a disc-shaped cover 3d fastened thereto at its rearward end 21b by such well known fastening means as the bolts 32. The tail 14b of the brush extends almost to the end :of the brush cylinder 21 by protruding through the inside cylindrical hole 21a of the brush cylinder 21; There is no contact between the tail of the brush 14b and the inside hole 21a of the brush cylinder 21 as a space is left lherebetween. This is clearly seen from FIG. 4 which shows a section of brush cylinder 21.

Diaphragms 18 are interposed between each cover 30 and the rearward ends 2111 of the brush cylinders 21. As can be seen from the section view of a brush holder in FIG. 4, the diaphragms 18 and the covers 3i) define the hydraulic reservoirs 16. The diaphragms 13 engulf the tails 14b of the brushes, thereby extending the hydraulic reservoirs 16 from the covers 31lto the space between the inside cylindrical holes 21a and the brush tails 14b. The dotted lines 13a in FIG. 4 indicate that the hydraulic reservoirs may be larger and the diaphragms accordingly stretched when the brushes 1 3 are worn down and have their remaining portion advanced or urged in contact with the commutator 12.

Any well known means can be used for attaching the brush holders to the dynamoelectric machine. In my specific embodiment, the rings 24 of the brush positioncrs are used to attach the brush holders it? to the guide posts of a dynamoelectric machine (not shown).

Master Cylinder The master cylinder 34, a section of which is clearly 'illustratedin FIG. 2, is provided for maintaining a constant pressure in the brush holders hydraulic reservoirs 16 whereby a constant force is exerted on the diaphragms 18 regardless of the stretch of the diaphragms or the positions of the brushes 14. The master cylinder 34 has a hydraulic reservoir 36 which is connected to each of the brush holder cylinders 21 through outlets in the master cylinder base 44.

The conduits 19 are attached to the elbows 19a at the outlets 44a. and each conduit leads to and is attached to a brush holder through the elbows 19:: which are attached to the outlets Zwtla in the brush cylinder covers 343.

The master cylinder 34 has a rear cover 38 with a hub 33a at its middle that has a bore 38b therethrough. The master cylinder cover 38 has an inside groove 38d therein to receive and position a compression spring 59. The cover 33 has a front end boss 3th: which fits with and is adjacent to ring 49. A diaphragm 42 has its periphery interposed between ring it? and the boss Mb of the master cylinder base 4-4 and it has the bolts 66 protruding therethrough to form a subassemhly of the master cylinder 34. .As shown in FIG. 2, the diaphragm can be molded so that it has a circular arcuate groove 42!) in order that when the diaphragm is advanced to the position shown by the dotted lines 42a, a smaller bending moment is exerted on points immediately adjacent to where the diaphragm is attached. As seen in FIG. 2, the subassembly of the base 44 with the diaphragm 42 and ring 40 is attached to the master cylinder cover 38 by a plurality of bolts 46 protruding through the boss 33c and the ring 4i A disc-shaped loader plate 48 which is adjacent to the diaphragm has a groove 42% therein to receive and position the ends of the compression spring 50 which are disposed between the loader plate 48 and the rear cover 38. The loader plate 48 has a threaded hole therein which is attached to the threaded end of a guide stud 51, the guide stud protruding through the rear cover bore 381). The guide stud 51 has a tapped hole 51a at one of its ends and it has a large headed screw 53 attached thereto. As seen in FIG. 8, the screw head 53a of the screw 53 is locked with a key 55 so that the spring 50 is kept compressed until the master cylinder 24 has fluid in it, as will be explained more fully hereinafter.

Assembling the Master Cylinder for Operation To assemble and put the master cylinder 34 into operation, the diaphragm 42 [has its peripheral edge interposed and clamped between ring 40 and the master cylinder base 44 by such means as the bolts 60 to form a subassembly. The loader plate 43 and spring 50 are positioned inside of the cover 38 and the guide stud 51 is inserted through the bore 38b of the master cylinder cover 38 and is screwed into the threaded hole 48w of the loader plate 48 to form the cover assembly. It should be noticed that the key 55 keeps the spring 50 compressed by locking the screw head 53a, which in turn restrains the loader plate 43, as illustrated in FIG. 8. The cover assembly is then bolted to the subassernbly consisting of the ring 40, diaphragm 42 and the base 44. The outlets 44a are connected to their respective outlets 30a and the master cylinder 34 is then filled with hydraulic fluid through the tap filling hole 440 in the base 44. The tap filling hole 440 is closed with plug 44 d and the compression spring 50- is then released by removing the key 55 to unlock the screw head 53a. The key 55 may then be assembled to the master cylinder cover 38 by a bolt 61 as shown in FIGS. 2 and 3. From FIG. 9 it is seen that the base 44 has another hole 45 besides the [hole 440. The hole 45 is used for the purpose of venting the hydraulic system.

Summary of Operation of System The operation of my new and improved system for maintaining and urging the brushes into contact with the commutator 12. is briefly as follows:

The diaphragms 18 in the brush holders .10 exert a constant force on the brushes 14 because the compression spring 50 is exerting a constant force onto the master cylinder diaphragm 42. When the tails of the brushes are advanced, such as for example to the dotted lines 18a shown in FIG. 4, the hydraulic system maintains a constant volume because the compression spring 50* advances the diaphragm 42. a suflicient distance to decrease the volume of its hydraulic reservoir 35 the same amount as the brush holder hydraulic reservoirs are increased by the stretching of the diaphragms 18. Since the volume remains constant and a constant force is exerted on the hydraulic system, a constant force urges the brushes 14 into contact with the commutator '12.

Even though I use a spring in my master cylinder to exert pressure on the hydraulic tfluid, this spring does not introduce the inherent disadvantages that were present in the prior art brush holders which were operated directly by springs. This is because in the prior art structures, the springs were elongated by magnitudes of an inch or more. On the other hand, my spring is extended no more than a fraction of an inch, as seen by the dotted lines 42a in FIG. 2. It is well known that the life or a spring is predicated on the number of times it is forced to approach its elastic lirnit. In my structure, the movement is so small in relation to the capacity of the springs that the springs should last indefinitely.

Therefore it can be said that my invention eliminates the disadvantages of prior art devices by providing a fluid means for automatically urging and maintaining a brush in contact with its commutator with a constant pressure. It further provides a brush holder which can be infinitely adjusted to exert a desired or optimum pressure on its respective brush. Also my invention provides a brush holder which has few parts and is so simple in construction that its brushes may be replaced very easily and quickly.

It is to be understood that the specific embodiment of the invention shown in the drawings and described in detail above is merely illustrative of one of the many forms which the invention may take in practice and that numerous variations and modifications thereof may be made Without departing from the scope of the invention as delineated in the appended claims which are to be construed as broadly as permitted by the prior art.

I claim:

1. In combination a rotating commutator electrically attached to a dynamoelectric machine, a plurality of brushes in electrical contact with said commuator, a plurality of brush holders to hold and urge each of said brushes in electrical contact with said commutator, said brush holders each having a hydraulic reservoir, diaphragms interposed between said reservoirs and said brushes whereby said hydraulic reservoirs exert pressure on said brushes by pressing said diaphragms against said brushes, said diaphragms stretching when said brushes are worn down whereby the volume of said brush reservoirs is increased and said brushes are urged and kept in contact with said commutator, and means for maintaining said hydraulic reservoirs at a constant pressure whereby a constant (force is exerted on said diaphragm-s regardless of their stretch or the position of said brushes, said means comprising a master cylinder having a hydraulic reservoir which is connected to each of said brush holder reservoirs, to form a constant volume system, said master cylinders hydraulic reservoir having a spring biased diaphragm exerting a constant force on it, said master cylinders diaphragm stretching when said brush holder diaphragms are stretched, whereby a constant volume is maintained in said hydraulic system and accordingly a constant force is exerted on said brushes at all times.

2. In combination: a brush holder for a dynamoelectric machine having a means responsive to a hydraulic reservoir for urging a brush into electrical contact with the commutator of a dynamoelectric machine, and a master cylinder connected to said hydraulic reservoir, said master cylinder having a subassembly including a ring and a base with a diaphragm held therebetween at its periphery, said diaphragm forming a hydraulic reservoir with said base, said diaphragm having a circular arcuate groove extending to points immediately adjacent to where said diaphragm is held, said diaphragm being biased by a compression spring whereby a constant force is exerted on said master cylinder reservoir.

3. In combination: a brush holder for a dynamoelectric machine having means for urging a brush into electrical contact with the machines commutator, said means being responsive to a hydraulic reservoir, and a master cylinder connected to said hydraulic reservoir, said master cylinder having a ring and a base with a diaphragm held therebetween at its periphery to form a subassembly, said diaphragm forming a master cylinder hydraulic reservoir with said base, said diaphragm having a circulararcuate groove near to points immediately adjacent to where said diaphragm is held, a cover assembly attached to said subassembly, said cover assembly being a cover assembled with a diaphragm loader plate by a guide stud protruding through said cover, a compression spring interposed between said loader plate and said cover, said guide stud having means for keeping said compression spring compressed until it is desired to release said spring to exert force on said diaphragm.

4. Master cylinder means for applying a constant pressure to a plurality of hydraulic reservoirs having diaphragms intermediately disposed in reiation to brush elements to urge said brush elements into contact with the commutator of a dynamoelectric machine comprising: a main hydraulic reservoir in communication with each of said brush elements reservoir, a diaphragm held in position by said master cylinder, and spring biasing means urging said master cylinders diaphragm against said main hydraulic reservoir, whereby said master cylinders diaphragm is stretched in relation to that of said brush elements diaphragms to maintain a constant volume and pressure in the system.

References Cited in the file of this patent UNITED STATES PATENTS 497,361 Thomson May 16, 1893 821,197 Speirs Aug. 29, 1905 884,049 Speirs Apr. 9, 1908 1,448,377 Bethel Mar. 13, 1923 1,896,164 Chandejsson Feb. 7, 1933 FOREIGN PATENTS 10,220 Great Britain of 1906 629,788 Great Britain Sept. 28, 1949 1,089,470 Germany Sept. 22, 1960 

3. IN COMBINATION: A BRUSH HOLDER FOR A DYNAMOELECTRIC MACHINE HAVING MEANS FOR URGING A BRUSH INTO ELECTRICAL CONTACT WITH THE MACHINE''S COMMUTATOR, SAID MEANS BEING RESPONSIVE TO A HYDRAULIC RESERVOIR, AND A MASTER CYLINDER CONNECTED TO SAID HYDRAULIC RESERVOIR, SAID MASTER CYLINDER HAVING A RING AND A BASE WITH A DIAPHRAGM HELD THEREBETWEEN AT ITS PERIPHERY TO FORM A SUBASSEMBLY, SAID DIAPHRAGM FORMING A MASTER CYLINDER HYDRAULIC RESERVOIR WITH SAID BASE, SAID DIAPHRAGM HAVING A CIRCULAR ARCUATE GROOVE NEAR TO POINTS IMMEDIATELY ADJACENT TO WHERE SAID DIAPHRAGM IS HELD, A COVER ASSEMBLY ATTACHED TO SAID SUBASSEMBLY, SAID COVER ASSEMBLY BEING A COVER ASSEMBLED WITH A DIAPHRAGM LOADER PLATE BY A GUIDE STUD PROTRUDING THROUGH SAID COVER, A COMPRESSION SPRING INTERPOSED BETWEEN SAID LOADER PLATE AND SAID COVER, SAID GUIDE STUD HAVING MEANS FOR KEEPING SAID COMPRESSION SPRING COMPRESSED UNTIL IT IS DESIRED TO RELEASE SAID SPRING TO EXERT FORCE ON SAID DIAPHRAGM. 